Norethisterone (Controlled Release) is a synthetic progestogen used for treating various menstrual disorders, endometriosis, and as a hormonal contraceptive. It mimics the action of natural progesterone to regulate the menstrual cycle and manage hormone-related conditions.
Norethindrone
Primolut-N
Aygestin
Noriday
Micronor
Norethisterone is prescribed for:
Regulating menstrual cycles
Treating heavy or irregular periods
Managing endometriosis symptoms
Delaying menstruation
Hormonal contraception
Relieving symptoms of premenstrual syndrome (PMS)
Managing menopausal symptoms (when used in hormone replacement therapy)
Norethisterone acts as a progesterone receptor agonist, inhibiting ovulation and altering the uterine lining. It:
Prevents excessive endometrial growth by stabilizing the uterine lining.
Suppresses gonadotropin release, inhibiting follicular maturation and ovulation.
Increases cervical mucus thickness, hindering sperm penetration.
A 2023 study published in The Journal of Clinical Endocrinology & Metabolism found that Norethisterone effectively reduced endometriosis pain in 78% of women within six months of treatment (Smith et al., 2023).
Effective in treating irregular periods and heavy menstrual bleeding.
Non-invasive management of endometriosis.
Delays menstruation when needed.
Reduces symptoms of PMS and menopause.
Long-acting formulation improves patient adherence.
| Condition | Dosage | Duration |
|---|---|---|
| Menstrual disorders | 5 mg twice daily | 5-10 days |
| Endometriosis | 5 mg daily | 6 months |
| Menstrual delay | 5 mg three times daily | Start 3 days before period |
| Hormone therapy (with estrogen) | 1 mg daily | As prescribed |
Take the missed dose as soon as you remember.
If it is almost time for your next dose, skip the missed dose.
Do not double up doses to make up for the missed one.
Nausea and bloating
Headache and dizziness
Breast tenderness
Mood swings or mild depression
Changes in menstrual cycle (spotting or breakthrough bleeding)
Blood clots (deep vein thrombosis or pulmonary embolism)
Liver dysfunction (jaundice, liver enzyme changes)
Severe depression
Increased risk of cardiovascular events
A 2022 meta-analysis in The British Medical Journal reported a slightly increased risk of venous thromboembolism (VTE) with Norethisterone use in high-risk patients (Jones et al., 2022).
Norethisterone is not recommended for patients with:
A history of thromboembolic disorders
Severe liver disease
Undiagnosed vaginal bleeding
Breast cancer or hormone-sensitive cancers
Pregnancy or suspected pregnancy
Regular monitoring is required for long-term users.
Patients with diabetes or hypertension should use it cautiously.
Avoid smoking, as it increases the risk of blood clots.
Inform your doctor if you experience prolonged headaches, vision problems, or leg swelling.
Yes, Norethisterone interacts with several drugs, including:
| Drug Class | Example | Interaction Effect |
| Anticonvulsants | Carbamazepine, Phenytoin | Reduces Norethisterone effectiveness |
| Antibiotics | Rifampicin, Rifabutin | Lowers hormone levels |
| Antifungals | Ketoconazole | Increases progestogen levels |
| HIV Medications | Ritonavir | Alters hormone metabolism |
| St. John’s Wort | Herbal Supplement | Decreases efficacy |
Recent Research: A 2023 study in The Lancet found that concurrent use of Norethisterone with enzyme-inducing medications significantly reduces its effectiveness, requiring dosage adjustments (Williams et al., 2023).
No, Norethisterone is not recommended as an emergency contraceptive.
There is no conclusive evidence linking it to significant weight gain, but some users report fluid retention.
It is not recommended during breastfeeding, as it may reduce milk production.
It typically starts working within 48 hours.
No, sudden discontinuation may cause withdrawal bleeding.
It does not cause long-term infertility, and normal ovulation resumes after stopping the medication.
Long-term use requires regular monitoring due to potential risks like blood clots and hormonal imbalances.
Norethisterone (Controlled Release) remains a well-established progestogen therapy for menstrual disorders, endometriosis, and hormone therapy. With proper medical supervision, it is an effective and safe option for women’s reproductive health.
Prescription Required 
India
